I personally enjoy circuit training because you engage muscles you didn’t know existed. CrossFit is a great way to get into this. It incorporates high intensity interval training (HIIT) one of my favourite ways to improve fitness fast. There’s the social aspect too. My first experience of CrossFit was training with my old rugby team. Intra-group competition is healthy because it urges you to achieve and doesn’t give time for slacking – It can be quite addictive!